The use of a cordless remote control device for operating domestic electronic devices such as personal computers is increasing. Furthermore the personal computer is expected to be very common as a general domestic information terminal in future.
However, there is a need for an easy to use input device for a general domestic personal computer for which the input operation is easy for the operator and which can be operated at any point in the room.
The conventional use of a remote control unit with a personal computer will now be described with reference to FIG. 6 and FIG. 7. FIG. 6 is a structural diagram of a remote control circuit of a conventional personal computer, and FIG. 7 illustrates the various signal codes thereof.
In the drawings, 30 is a remote control unit, 31 is a control input unit, 32 is a transmitter controller circuit, 33 is a transmitter circuit, 34 is a main device, 35 is a receiver circuit, 36 is a receiver controller circuit, 37 is an operation unit, 38 is an operation detecting circuit, 39 and 41 are display circuits, and 40 is a control detection circuit.
The control input unit 31 is operated selectively corresponding to the various operating functions of the main device 34 such as for example a personal computer, and outputs a control signal in some digital code. FIG. 7 shows an example of an 8 bit control signal output. This control signal is next input to the transmitter controller circuit 32. In the transmitter control circuit 32, the transmitter circuit 33 and control detection circuit are connected. In the transmitter controller circuit 32, based on the control signal input, as shown in FIG. 7, a 16 bit data code is generated from the control signal and an inverted control signal which has every bit of the control signal inverted, and in order to prevent interference with the signals of other devices, a 16 bit custom code is produced from a limited code and the inverted limited code. The non-inverted codes and the inverted codes are discriminated in the main device 34 and when they are the corresponding codes, a provision is made that the following operation can be made, in order to prevent erroneous operation. The 16 bit custom code and data code are combined to form a 32 bit control data signal which is sent to the transmitter circuit 33. Also at this point, from the transmission controller circuit 32 the input control signal is passed through the control detection circuit 40 and the command given is displayed by the display circuit 41. Then an infra-red command signal is emitted by the transmitter circuit 33 based on the control data signal input, and is transmitted to the main device 34. The receiver circuit 35 of the main device 34 detects with an optical detector element the infra-red ray control command signal transmitted by the remote control unit 30. The control command signal detected by the optical detector element is output from the receiver circuit 35 as a code with the same contents as the control data signal, and is input to the receiver controller circuit 36, and is then subject to erroneous operation prevention processing as follows.
The limited code and the inverted limited code of the custom code are added, and a test is made as to whether all 8 bits are 1. If it is detected that at least one bit of the sum is 0, the following operation is not carried out. When, however, all the bits are 1, the limited code is compared with a limited code stored previously in the main device 34, and if they are in agreement next the data code is subject to erroneous operation prevention processing in the same way as the custom code. In the normal case then the control signal is decoded. If an abnormality is detected, and the processing in progress is abandoned, then with the command signal to be reinput a reset is done and the same processing is carried out. The decoded control signal is output from the receiver controller circuit 36 to the operation unit 37 based on the contents of the control signal, and the operation selected on the remote control unit 30 is carried out by the operation unit 37. Additionally the operating state of the operation unit 37 is converted by the operation detecting circuit 38 to a display signal, and displayed by the display circuit 39.